Include in docs how to trigger an immediate pull

doc/user/project/repository/repository_mirroring.md

@@ -356,6 +356,24 @@ a [Push event webhook](../integrations/webhooks.md#push-events) to trigger an im
 pull to GitLab. Push mirroring from GitLab is rate limited to once per minute when only push mirroring
 protected branches.
 
+### Configure a webhook to trigger an immediate pull to GitLab
+
+Assuming you have already configured the [push](#setting-up-a-push-mirror-to-another-gitlab-instance-with-2fa-activated) and [pull](#pulling-from-a-remote-repository-starter) mirrors in the upstream GitLab instance, to trigger an immediate pull as suggested above, you will need to configure a [Push Event Web Hook](../integrations/webhooks.md#push-events) in the downstream instance.
+
+To do this:
+
+- Create a [personal access token](../../profile/personal_access_tokens.md) with `API` scope.
+- Navigate to **Settings > Webhooks**
+- Add the webhook URL which in this case will use the [Pull Mirror API](../../../api/projects.md#start-the-pull-mirroring-process-for-a-project-starter) request to trigger an immediate pull after updates to the repository.
+
+  ```plaintext
+  https://gitlab.example.com/api/v4/projects/:id/mirror/pull?private_token=<your_access_token>
+  ```
+
+- Ensure that the **Push Events** checkbox is selected.
+- Click on **Add Webhook** button to save the webhook.
+- To test the integration click on the **Test** button and confirm GitLab does not return any error.
+
 ### Preventing conflicts using a `pre-receive` hook
 
 CAUTION: **Warning:**